Process for Dyeing Ramie Sliver and Method for Preparing Yarn

ABSTRACT

A process for dyeing ramie sliver, comprising: 1.) pretreatment: cooking the ramie sliver for 8-12 minutes in a cooking reagent in a bath ratio of 1:4-10, the cooking reagent is a 1-3 g/L aqueous solution of a penetrating agent; and 2.) dyeing: dyeing the cooked ramie sliver in an active dye in a bath ratio of 1:4-10. Also disclosed is a method for preparing ramie yarn. The ramie sliver dyed according to the present invention improves the properties of ramie fibers, such that the ramie fibers are less likely to break; and the ramie fibers are less likely to harden, avoiding poor drawing, needle breakage and missing stitches during carding and coalescing in post-procedures, thus achieving the purpose of smooth yarn spinning. Also disclosed is a method for preparing ramie colored-spun yarn.

The present application claimed priority based on the patent applicationentitled by “Process for dyeing ramie sliver and method for preparingyarn” filed with the Chinese Patent Office (No. 201110179694.6) on Jun.29, 2011, all contents of which are combined in the present applicationby reference.

FIELD OF INVENTION

The present invention relates to cloth dyeing technical field, inparticular, a process for dyeing ramie slivers.

BACKGROUND OF THE INVENTION

Ramie is a fiber crop having good quality, high yield and characteristicof China, and the gross output of ramie in China occupies 90% of that ofthe world. Ramie fiber has the advantageous features of stronghydroscopicity, fast heat dissipation, corrosion resistance andbacterial inhibition, soft luster, recyclability, environmentalfriendliness and the like, as well as excellent wearability.

As production technology develops and people's living standard raises,ramie is used more and more, mainly for manufacturing ramie cloth, suchas Chinese linen. Now, dyeing of ramie mainly lies in ramie yarn dyeingand stock (refined dry flax) dyeing, both of which have succeeded.However, the style of the colored fabric weaved with the dyed ramieyarns is relatively fixed, and dyeing of refined dry flax has a lowyield, resulting in severe waste. Although dyeing of ramie sliversexists currently, and it greatly increase yield and achieve a varyingcolorful effect, which is difficult to be achieved by yarn dyeing, bycoalescing ramie slivers having different colors and blend spinning intoyarns, the existing ramie sliver dyeing technology generally uses thetop dyeing technique conventional in wool or cotton spinning industry;moreover, the dyed fiber slivers are likely to break in coalescing anddrawing, and the fibers are likely to harden due to no curling and poorcohesion of ramie fibers, readily leading to poor drawing, needlebreakage and missing stitches during carding and coalescing inpost-procedures, thus it is difficult to spin smoothly.

SUMMARY OF THE INVENTION

Directing to these disadvantages, the present invention provides aprocess for dyeing ramie slivers, by which the ramie slivers dyed is notliable to break and harden and enables smooth yarn spinning.

In order to achieve the above purpose, the invention provides thefollowing technical solution: a process for dyeing ramie slivers,comprising

1) pretreatment: steaming ramie slivers for 8-12 min at a bath ratio of1:4-10 with a 1-3 g/L aqueous solution of a penetrant as a steamingagent;

2) dyeing: dyeing the steamed ramie slivers in an active dye at a bathratio of 1:4-10.

Preferably, the dyeing in step 2) comprises the following process:adding ramie slivers to a dissolved active dye at atmospherictemperature, stirring for 5-10 min; adding a salt solution, increasingtemperature to 60° C.-70° C., running for 5-8 min, adding sodiumcarbonate solution, and running for 40-60 min while holding thetemperature; taking the ramie slivers out, and sequentially performingwashing with clear water, neutralizing with diluted acid, soaping, andwashing with cold water.

Preferably, the dyeing process further comprises 3) post-treatment:subjecting the dyed ramie slivers to color fixing and oiling.

Said color fixing is carried out by immersing ramie slivers in anaqueous solution containing 2-4% (o.w.f) of a color fixing agent and2-5% (o.w.f) of a softener at 35° C.-50° C. for 10-20 min;

Said oiling is carried out by immersing the color-fixed ramie slivers inan aqueous solution containing 2-3 g/L of an oil agent at 60° C.-70° C.for 20-30 min.

Preferably, said soaping is carried out by washing the ramie slivers ina solution of 1-2 g/L of detergent at 90° C.-100° C. for 10-15 min.

Preferably, the ramie slivers in step 1) are set to have a coiler shape.

The present invention further provides a preparation method of ramiespun yarn, and the technical solution thereof is as follows: a methodfor preparing ramie colored-spun yarn, comprising the following steps:

(1) preparing ramie fibers into ramie balls having a coiler shape;

(2) steaming ramie balls for 8-12 min at a bath ratio of 1:4-10 with a1-3 g/L aqueous solution of a penetrant as a steaming agent;

(3) dyeing the ramie balls steamed in step (2) in an active dye at abath ratio of 1:4-10;

(4) subjecting the ramie slivers dyed in step (3) to color fixing andoiling;

(5) dewatering and drying the ramie slivers from step (4); standing formore than 24 h;

(6) coalescing, drawing and combing the ramie slivers after standing instep (5); coalescing and drawing the combed ramie slivers; and

(7) spinning the ramie slivers from step (6) into yarns at 20-30° C. andrelative humidity of 70-90%.

20-30° C. and relative humidity of 70-90%.

Preferably, drying in step (5) is required to achieve a moisture regainof 7-10% and an oil content of 0.5-1.5%.

Preferably, the ramie sliver used for spinning yarn in step (7) has atleast one color.

In the present invention, ramie fibers are firstly made into ramie ballshaving a coiler shape and certain weight, subsequently bagged, caged andhoisted to a yarn dyeing machine for dyeing. The dyeing process involvessteaming ramie balls with a steaming liquor containing a penetrant andthen dyeing. In order to guarantee the subsequent spinnability of theramie fibers, it is further needed to perform oiling treatment forimproving spinnability to the dyed ramie fibers, followed by dewateringand drying, thereby preparing colored ramie fiber slivers meeting therequirements of spinning process. The colored ramie fiber slivers arethen subjected to fiber loosening, coalescing and drawing, and spunafter combing. The colored ramie fiber slivers can be spun solely orblend-spun with other weaving fibers to obtain ramie or its blend yarnshaving different characteristics and different colors.

The dyed ramie slivers in the present invention improves the propertiesof ramie fibers, such that the ramie fibers are not liable to break incoalescing and drawing; and the ramie fibers are not liable to harden,avoiding poor drawing, needle breakage and missing stitches duringcarding and coalescing in post-procedures, thus achieving the purpose ofsmooth yarn spinning.

The preparation method of ramie spun yarn according to the presentinvention effectively solves the technical problem in production oframie sliver colored-spun yarn, and facilitates diversity of product andincrease of added value or ramie product to thereby obtain highereconomic benefit. Colorful ramie products having different elements canbe prepared by the preparation process and method according to thepresent invention.

DETAILED EMBODIMENTS

A preparation method of ramie spun yarn, comprising the following steps:

1. preparing ramie fibers into ramie balls having a coiler shape and aweight of 4-5 kg/ball

main process parameters sliver weight 10-20 g/m thickness of the shapedramie balls 200-250 mm central hole of the shaped ramie balls Φ80-90 mm

2. loading the ramie balls into a nylon net bag, relatively fixing theramie fiber slivers along axial direction with a proper tightness toprevent tangle thereof:

3. loading the ramie balls fixed as required to a suspended cage;

4. placing the suspended cage containing the ramie fiber slivers into ayarn dyeing pot;

5. dyeing the ramie fiber slivers in a yarn dyeing pot (model A11WIN-55,produced by Fong's National Engineering Co., Ltd, Hong Kong).

A suspended cage capable of holding ramie balls is designed taking theadvantages of AUwin series dyeing vessels produced by Fong's NationalEngineering Co., Ltd., and placed into the dyeing vessel for dyeing. TheAUwin series dyeing vessels produced by Fong's National Engineering Co.,Ltd. have the advantages of energy saving, high efficiency, ability ofpressure dewatering, and possession of AIR advanced intelligent washingsystem.

The ramie sliver dyeing process comprises the following process flow:pretreatment->dyeing->post-treatment;

Dyeing aid: Penetrant JFC produced by Hubei Jianli Chemical IndustryCo., Ltd. Detergent 805 produced by Hubei Jianli Chemical Industry Co.,Ltd. Color fixing agent produced by Shenyang Chemical industry Co., Ltd.Dye produced by Yorkshire Chemicals Holdings Ltd., active dye Saltsodium chloride produced by Hunan salt industry Co., LTD. Alkali sodiumcarbonate produced by Zhuzhou Zhicheng Chemical Industry Co., Ltd.Softener produced by Clariant Chemicals Ltd. Ramie oiling agent producedby Beijing CTA-Tex Chemicals Co., FD-ZY06A, FD-ZY06B Ltd

1) Pretreatment

The pretreatment is for the purpose of removing the small quantity ofoil and other aids attached on the ramie slivers, which is beneficial tofiber coloring and capable of guaranteeing the dyeing performance of thefibers.

Main Process Parameters:

Penetrant JFC 1 g/L Bath ratio 1:4-10 Temperature 100° C. Time 10 minCirculation completely internal flow

Key points: completely-internal-flow is adopted in the circulation fortemperature increase, where the rate of temperature increase is set tobe the fastest, and the pump speed is 90%. After pretreatment isfinished, washing with cold water is conducted once for 5 min, and thetank is opened for checking.

2) Dyeing

Dye: active dye, the amount thereof varies according to colors

Bath ratio: 1:410

Dissolved dye is added at atmospheric temperature, followed by runningfor 5 min; dissolved salt is added and then temperature is increased to60° C., followed by running for 5 min; dissolved sodium carbonate isadded, followed by running for 40-60 min while holding the temperatureat 60° C., and then a sample is taken. The color is checked. If thecolor is correct, water is discharged, and washing with clear water isconducted once for 5 min; subsequently, glacial acetic acid is added forneutralization (HAC 2-4 g/l), and water is discharged after running atatmospheric temperature for 5 min. Soaping is performed once (detergent1-2 g/l, temperature 90-100° C., time 10 min), then water washing andoverflow water washing are carried out sequentially, followed by washingwith 80° C. water once for 5 min (washing with hot water is performedagain if the color is very deep) and washing with cold water for 1-2times each for 5 min. Lubrication treatment is carried out (color fixingagent is added if the color is deep) at 40° C. for 10 min, and thenwater is discharged out of the cage.

In the steps in which the ramie balls are disposed in the dyeing vessel,the rates of temperature increase and decrease are set to be thefastest, expect for that the rate of temperature increase in dyeing iscontrolled at 2° C./min, so that the retention time of the ramie ballsin the dyeing vessels is shortened as much as possible, and the impactof liquid flow on the ramie balls is reduced, thereby avoiding tangle.

Key points of dyeing: the dyes having low substantivity and bettermigrating property (especially dyes of medium and light color) should beused. The dyes and aids should be substantially dissolved beforeaddition. Feed speed should be controlled severely, and dye is fed at aspeed of 50% for 10 min; and the aids are fed at a speed of 70% for 5min. Dyeing is performed for 40-60 min with rate of temperature increasecontrolled at 2° C./min. Bidirectional circulation is adopted in dyeing,comprising external flow at a pump speed of 60% for 2 min and internalflow at a pump speed of 90% for 4 min, and internal-flow starting isadopted.

3) Post-Treatment

The purpose of post-treatment is to fix color for improving colorfastness of dyeing and to oil for enabling smooth carding.Post-treatment is performed under the environment bidirectional flowcomprising internal flow at a pump speed of 80% for 4 min and externalflow at a pump speed of 40% for 1 min.

Main Process Parameters for Color Fixing:

Temperature 40° C. Time 10 min Color fixing agent 2-4% Softener 2-5%

Main Process Parameters for Oiling:

Temperature 60° C. Time 20 min Oiling concentration 2-3 g/l

6. Dewatering the dyed ramie fiber slivers which have been subjected tocolor fixation and oiling.

7. Dying the dyed and dewatered ramie fiber slivers (radiofrequencydryer)

A moisture regain of 7-10% is required after drying;

An oil content of 0.5-1.5% is required after drying.

8. Standing and incubating the treated ramie fiber slivers for more than24 h to eliminate partial internal stress of fibers and keepinternal-external equilibrium of the regain.

9. Coalescing and drawing the dyed ramie fiber slivers subjected tostanding and incubating on a double-apron drawing frame by using alow-speed, light-weight and small draft process, to achieve the purposeof reducing fiber hardening and loosening the fibers, so as to benefitthe yarn spinning process.

10. Coalescing and drawing the dyed ramie fiber slivers treated with thedouble-apron drawing frame again on a needle-plate drawing frame toimprove the evenness of the ramie slivers.

11. Removing part of flaws and short fibers from the coalesced dyedramie Fiber slivers on a ramie comber by using a process of “low speed,fine combing and light weight”, so as to satisfy the requirement ofhigh-quality yarn. A smooth roll is used instead of a grooved roll atthe sliver outlet to improve cohesion of fibers and thereby facilitatethe subsequent production. Different process schemes may be made basedon different raw materials, for example, this procedure may be canceledto meet any requirements for the style and the like of product.

12. Coalescing and drawing the combed dyed ramie fiber slivers on adrawing frame for 3-5 times. The coalescing process is performed at alow speed and a light weight by using a trumpet with a perfectpressurizing automatic stopper, smooth passage and small diameter, toimprove the evenness and smoothness of the fiber slivers, to ensureuniform mixing and to enable the slivers to shape well.

13. Treating roving according to a process principle of low speed, lightweight and appropriate twist factor.

14. Treating spun yarn at a low speed and an appropriate pressure with asmall draft and appropriate setting and tension, to reduce hairiness andbroken ends and improve evenness of the slivers.

15. Keeping, a relatively high environment temperature and humidityduring the yarn spinning process.

Temperature 20-30° C. Relative humidity 70-90%

16. carrying out color mixing of dyed ramie fiber slivers by means ofsliver mixing as well as other means.

The invention is described in detail in combination with the followingexamples, and such description is merely for demonstration andexplanation, without any intention of limitation to the protection scopeof the invention.

Example 1 Production of 24 Nm Coffee-Colored Ramie Knitting yarn

1. Ramie fiber slivers were made into ramie balls having a coiler shape

Weight of ramie fiber slivers: 10±1 g/m

Shaping height of the ramie balls: 200-250 mm

Shaping weight of the ramie balls: 4500-5000 g/ball

The central hole diameter of the shaped ramie balls: Φ80-90 mm

2. The ramie balls were loaded into a nylon net bag, the ramie fiberslivers were fixed along the axial central hole from the external with aproper tightness to prevent tangle thereof.

3. The fixed ramie balls were loaded to a suspended cage;

4. The suspended cage containing the ramie fiber balls were placed intoa yarn dyeing machine;

5. The ramie fiber slivers were dyed.

Dyeing process flow: pretreatment->dyeing->post-treatment

(1) Pretreatment

pretreatment aids:

penetrant JFC: 1 g/L

bath ratio: 1:4

temperature: 100° C.

time: 10 min

circulation: entire internal and external flow

pretreatment pump power: 90% for internal flow, 40% for external flow

time: 5 min for internal flow, 3 min for external flow

-   -   Circulation was carried out in such manner that even dyeing is        ensured and tangle of fiber slivers is prevented.

(2) Dyeing

dye: active dye (coffee-colored) 3BE-N 0.63%, 3BF-N 0.51%, B: 23%.

Bath ratio: 1:4

Dissolved dye was added at atmospheric temperature, followed by runningfor 5 min; dissolved salt was added and then temperature was increasedto 60° C., followed by running for 5 min; dissolved sodium carbonate wasadded, followed by running for 40-60 min while holding the temperatureat 60° C. The color is checked, if the color was correct, water wasdischarged, and washing with clear water was conducted once for 5 min;subsequently, glacial acetic acid was added for neutralization (HAC2-40), and water was discharged after running at atmospheric temperaturefor 5 min. Soaping was performed once (detergent 1-2 g/l, temperature90-100° C., time 10 min), then water washing and overflow water washingwere carried out sequentially, followed by washing with 80° C. wateronce for 5 min (washing with hot water was performed again if the colorwas very deep) and washing with cold water for 1-2 times each for 5 min.Lubrication treatment was carried out (color fixing agent was added ifthe color was deep) at 40° C. for 10 min, and then water was dischargedout of the cage.

Dyeing pump power: internal 90%, external 80%

Circulation time: internal 4 min, external 2 min

(3) Post-Treatment

acid washing: HAC 2-4 g/L 10 min

color fixing: 10° C. 10 min

color fixing agent: 2%

softener: 5%

-   -   6. The dyed ramie fiber slivers subjected to color fixing and        washing was immersed in oil to ensure the spinnability of the        fibers.

Main Process Parameters for Oiling

Ramie oiling agent: FD-ZY06A, FD-ZY06B 2.5 g/L

Bath ratio: 1:7

Time: 6 h

Temperature: 55° C.

pH value: 8.5

-   -   7. The oiled dyed ramie fiber slivers was dewatered with a        centrifugal dewatering machine, and the dyed ramie fiber balls        were parallely placed into a dewatering machine one by one for        dewatering.

Required moisture content after dewatering: 45-55%

-   -   8. drying

Using a radiofrequency dryer: model FTDW85, produced by

Fong's National Engineering Co., Ltd.

Time 5 m/h

Regain after drying: 7-10%

Oil content: 0.5-1.0%

-   -   9. operation essentials    -   (1) Ramie slivers should be placed in parallel in the production        process and should not be disordered.    -   (2) After pretreatment was finished, the vessel should be        opened, and the fastening screws should be readjusted.    -   (3) Internal and external circulation time and pressure of the        circulation pump should be adjusted well in the dyeing process        to decrease hairiness as mush as possible.    -   10. The dyed ramie fiber slivers were allowed to stand and be        incubated for more than 24 h under natural conditions.    -   11. The dyed ramie fiber slivers were coalesced and drawn to        reduce hardening of fiber and loose the fiber.

Machine model: BR221 apron drafting machine

Coalescing number: 6-8

Draft: 6-9

Feed weight: 10-15 g/m

Front roller speed: 50-120 m/min

Setting for drawing: front roller-middle roller 170 mm

-   -   middle roller-rear roller 240 mm    -   12. The dyed ramie fiber slivers treated with a double-apron        drawing frame were coalesced and drawn again to improve evenness        of the ramie slivers.

Model CZ304A gill faller

Coalescing number: 6-8

Draft: 6-9

Feed weight: 10-15 g/m

Sliver discharge weight: 10-12 g/m

Front roller speed: 35/55 m/min

Needle plate beats: 800-1000/min

Needle plate density: 7-10 needles/inch

Setting in drawing: 45-55 mm

-   -   13. The coalesced dyed ramie fiber slivers were combed to remove        part of short fibers and impurities and improve quality of the        fiber.

Machine model: B311 comber

Pulling setting: 30-45 mm

Combing setting: 1 mm

Feeding: 15-19 T

Cylinder: 90-100/min

Sliver discharge weight: 45-55 g/5 m

-   -   14. The combed dyed ramie fiber slivers were subjected to        coalescing and drawing for 3-4 times to obtain even final        coalesced slivers meeting the requirements of spinning process.

Machine model: gill faller

Main Process Parameters:

Setting in drawing: 40-55 mm

Needle plate density: 10-18 needles/inch

Needle plate beats: 390-800/min

Draft: 6-9

Coalescing number: 6-10

Sliver discharge weight: 8-15 g/m

-   -   15. The dyed ramie fiber slivers were spun into slubbing

Main Process Parameter

Front roller speed: 100-200 r/min

Spindle speed: 200-350 r/min

Draft: 5-10

Twist factor: 18-22

Count of delivery: 1-2 Nm

-   -   16. The slubbing was spun into roving

Main Process Parameters

Front roller speed: 55-90 r/min

Spindle speed: 200-450 r/min

Draft: 5-10

Twist factor: 18-22

Count of delivery: 2-4.5 Nm

-   -   17. Yarns were spun

Main process parameters

Front roller speed: 80-110 r/min

Spindle speed: 500-7000 r/min

Draft: 10-20

Twist factor: 90

Count of delivery: 24 Nm

-   -   18. drum (equipped with an electronic yarn clearer)

Drum speed: 300-400 m/min

Main parameters of the electronic yarn clearer

D: 2.0

DL: 2.5 cm

-   -   The finally produced ramie yarns were detected. The yarns have        the features of soft luster, cleanness, less hairiness, etc.,        and are suitable for use in woven or knitted ramie products.

Example 2 Production of 60 Nm Ramie-Viscose Gray Spun Yarn (30%ramie/70% viscose)

-   -   1. Ramie fiber slivers were dyed into black according to steps        1-10 of Example 1.    -   2. Combed black ramie fiber slivers were produced according to        steps 11-13 of Example 1.    -   3. The Combed black ramie fiber slivers were coalesced and drawn        to form even semi-finished product satisfying process        requirements.

Main Process Conditions:

Needle plate beats: 600-800/min

Needle plate specification: 10-14 needles/inch

Draft: 5-9

Sliver discharge weight: 9-10 g/m (dry weight)

-   -   4. inherently white ramie fiber slivers were pre-coalesced and        drawn to form even semi-finished product satisfying process        requirements, in which the main process conditions were        identical with those provided in step 3.    -   5. Inherently white viscose fiber slivers were pre-coalesced,        coalesced, and drawn to form even semi-finished product        satisfying process requirements, in which the main process        conditions were identical with those provided in step 3.    -   6. Process flow for production of colorful fiber slivers:

Pre-coalescing of inherently white ramie fiber slivers Pre-coalescing ofblack ramie fiber slivers {close oversize brace} Pre-coalescing ofinherently white viscose fiber slivers −> primary coalescing−> secondarycoalescing−> and coalescing for the third time−> final coalescing−>slubbing−> roving−> yarn−> drum

-   -   7. Colorful fiber slivers satisfying process requirements were        produced according to step 14 as sated in example 1.    -   8. Slubbing is spun according to step 15 as stated in example 1.    -   9. Roving is spun according to step 16 as stated in example 1.    -   10. Yarns were spun according to step 17 as stated in example 1.    -   11. Cheeses were produced according to step 18 as sated in        example 1.

In the production method described above, ramie fiber slivers were dyedand then prepared into blend colored-spun yarns having unique style byusing a ramie spinning apparatus. The obtained yarns have unique styleand good luster, and can lead the fashion trend of ramie textiles;meanwhile, they enable enrichment of ramie textile products and addedvalue increase of the products.

The above is merely preferred embodiments of the present invention. Itshould be indicated that, those skilled in the art may make someimprovement and retouch on the premise of not deviating from theprinciple of the present invention, and such improvement and retouchshould be considered within the protection scope covered by theinvention.

1. A ramie sliver dyeing process, comprising (1) pretreatment: steamingramie slivers for 8-12 min at a bath ratio of 1:4-10 with a 1-3 g/Laqueous solution of a penetrant as a steaming agent; (2) dyeing: dyeingthe steamed ramie slivers in an active dye at a bath ratio of 1:4-10. 2.The ramie sliver dyeing process according to claim 1, characterized instep (2) dyeing comprising the following procedures: adding ramieslivers to a dissolved active dye at atmospheric temperature, stirringfor 5-10 min; adding a salt solution, increasing temperature to 60°C.-70° C., running for 5-8 min, adding sodium carbonate solution, andrunning for 40-60 min while holding the temperature; taking the ramieslivers out, and sequentially performing washing with clear water,neutralizing with diluted acid, soaping, and washing with cold water. 3.The ramie sliver dyeing process according to claim 1 characterized infurther comprising (3) post-treatment: subjecting the dyed ramie sliversto color fixing and oiling, said color fixing is carried out byimmersing ramie slivers in an aqueous solution containing 2-4% (o.w.f)of a color fixing agent and 2-5% (o.w.f) of a softener at 35° C.-50° C.for 10-20 min, said oiling is carried out by immersing the color-fixedramie slivers in an aqueous solution containing 2-3 g/L of an oil agentat 60° C.-70° C. for 20-30 min.
 4. The ramie sliver dyeing processaccording to claim 2, characterized in that said soaping is carried outby washing the ramie slivers in a 1-2 g/L of detergent at 90° C.-100° C.for 10-15 min.
 5. The dyeing process according to claim 1, characterizedin that the ramie slivers in step (1) are set to have a coiler shape. 6.A method for preparing ramie colored-spun yarn, comprising the followingsteps: (1) preparing ramie fibers into ramie balls having a coilershape; (2) steaming ramie balls for 8-12 min at a bath ratio of 1:4-10with a 1-3 g/L aqueous solution of a penetrant as a steaming agent; (3)dyeing the ramie balls steamed in step (2) in an active dye at a bathratio of 1:4-10; (4) subjecting the ramie slivers dyed in step (3) tocolor fixing and oiling; (5) dewatering and drying the ramie sliversfrom step (4); standing for more than 24 h; (6) coalescing, drawing andcombing the ramie slivers after standing in step (5); coalescing anddrawing the combed ramie slivers; and (7) spinning the ramie slivers'from step (6) into yarns at 20-30° C. and relative humidity of 70-90%.7. A method for preparing ramie colored-spun yarn according to claim 6,characterized in that the drying in step (5) is required to achieve amoisture regain of 7-10% and an oil content of 0.5-1.5%.
 8. A method forpreparing ramie colored-spun yarn according to claim 6, characterized inthat the ramie sliver used for spinning yarn in step (7) has at leastone color.
 9. The ramie sliver dyeing process according to claim 2,characterized in further comprising (3) post-treatment: subjecting thedyed ramie slivers to color fixing and oiling, said color fixing iscarried out by immersing ramie slivers in an aqueous solution containing2-4% (o.w.f) of a color fixing agent and 2-5% (o.w.f) of a softener at35° C.-50° C. for 10-20 min, said oiling is carried out by immersing thecolor-fixed ramie slivers in an aqueous solution containing 2-3 g/L ofan oil agent at 60° C.-70° C. for 20-30 min.